Device for producing polar oscillograms.



L. W. CHUBB'.

DEVICE FOR PRODUCING POLAR OSCILLOGRAMS.

APPLICATION FILED DEC-31.1913.

Patented Mar. 14, 1916.

) VOL TAGS zmos ATTORNEY THE COLUMBIA FLANOGRAPH cm, WASHINGTON. D. c.

UNITED STATES PATENT OFFTQE.

LEWIS W. CHUBB, 0F EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOB TO WESTING-HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYL-VANIA.

DEVICE FOR PRODUCING POLAR OSCILLOGRAMS.

Application filed December 31, 1913.

To all whom it may concern:

Be it known that I, LEWIS W. CHUBB, a citizen of the United States, anda resident of Edgewood Park, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in Devices forProducing Polar Oscillograms, of which the following is a specification.

My invention relates to oscillographic devices and particularly todevices for making photographic records having polar or circularcoodinates.

The object of my invention is to provide a device for photographing areflected ray of light from an oscillograph upon a sensitized circularplate or film.

Heretofore, oscillographs have been provided with films or fallingplates which passed in front of shutters at definite speeds to exposethem to the reflected rays of light from galvanometers for producingcurves having rectangular coordinates. In many cases, as when analyzingthe waves for harmonies and when computing the power represented bycurves, it is desirable to convert the curves represented by rectangularcoordinates into curves having circular or polar coordinates. Thisreplotting of the curves requires considerable time, and Se rious errorsare possible by reason of mistakes made in transferring the figures. Toovercome the aforesaid difliculties, .1 provide a means forphotographing rays of light in polar or circular coordinates, ashereinafter described.

Figure 1 of the accompanying drawings is a front elevational view of aphotographic device embodying my invention. Fig. 2 is a section takenalong the line IIII of Fig. 1. Fig. 3 is a side view, partially inelevation and partially in section, of the device shown in Fig. 1, and adriving motor connected thereto, and Fig. 4: is a specimen curve sheetmade with the apparatus embodying my invention.

A hollow ribbed receptacle 1, having a cover 2 with a slit 3 therein, isarranged to fit any well known type of oscillograph (not shown). Thecover 2 has a substantially rectangular raised portion 4 which projectsover the edge of the same and has a recess 5 therein in which operates ashutter 6 having a tapered slit 7 in a handle 8 attached to its lowerend. The shutter 6 is maintained in the recess 5 by a plate 9 whichSpecification of Letters Patent. Pateni'di Serial No. 809,795.

is attached to the raised portion l of the cover member 2 by a pluralityof screws 10. The plate 9 is slightly wider than the raised portion A ofthe cover 2 so that it may be slipped in the grooves (not shown) usuallyprovided on an oscillograph for that purpose. The handle 8 of theshutter has a vertical slot 11 to receive a screw 12, and a horizontalslot 13 to receive a pin 14 that is attached to one end of a lever 15having a pivotal support upon a pin 16. The receptacle 1 is providedwith a plurality of projections 17, and the cover 2 is provided with anequal number of projections 18 which cooperate to fasten the cover 2 andthe receptacle 1 together.

A synchronous motor 19 having a shaft 20 is attached to the receptacle 1by any suitable means. lhe shaft 20 projects into the receptacle 1 andhas attached thereto, near its end, a sleeve 21 upon which is mounted asupporting plate 22. The sleeve 21 is threaded to receive a nut 23 whichpresses a washer 2& against a circular sensitive film or plate 25.

As is known by those versed in the art, an oscillograph is essentially agalvanometer the vibrations of which are synchronously reflected upon asensitized plate or film to reproduce a curve which is a picture of theperformance of the voltage or current under consideration. Hence, nofurther description of an oscillograph is deemed necessary for a clearunderstanding of my invention.

A circular film 25 is inserted in the circular receptacle or casing 1 onthe shaft 20 and the cover 2 is securely clamped in place in a darkroom. The device is then attached to an oscillograph (not shown) byinserting the plate 9 behind the usual slots provided on an oscillographfor that pur pose. The usual oscillograph has a slit in it whichcorresponds to the slit 3 in the cover 2 so that a ray of light from theoscillograph (not shown) may be transmitted to the film The motor 19 isstarted and runs at synchronous speed. V'Jhen synchronism is reached,the lever 15 is depressed, thus moving the shutter 6 upwardly andexposing the film to a rapidly vibrating ray of reflected light. Usuallya base line or zero circle is drawn on the film by a subsequentexposure, with the element or galvanometer of the oscillograph sodisconnected that it does not vibrate. Qhis will produce a perfectcircle upon the sensitized plate.

In Fig. 4c of the drawings are shown two curves, one representing thecurrent taken by a 5 lzilovolt ampere transformer and the other thevoltage of the same, while the zero line for each is given.

The device is particularly adaptable to photographing periodic waves,and the shutter need remain open only suificient time to equally exposethe entire Since the film is rotated in synchronism with the periodicwave, the time of exposure depends only upon the time required toequally expose the whole film. The device may be adapted forphotographing transient or non-periodic waves if the openin in theshutter is made rectangular in form.

The slit 7 in the shutter 6 is tapered to equalize the time of exposureof the difi'erent points on the dish film. That is, the slit 7 is soshaped that, when the slit 3 is opened by moving the shutter 6 the outerportions of the dish 25 receive the light before the inner portions,and, when the slit 3 is closed, the outer portions receive the lightlonger than the inner portions, thus compensating, in a certain manner,for the diii erence in peripheral speed of the various portions of thedisk. Should it be desired to photograph a true polar curve with itszero at a point, the slit may be extended to the center oi the cover 2,as will be readily understood by those versed in the art. The motor 19may be of any type but it must be operated in synchronism with thecircuits the curves of which are being photographed.

While I have described my invention in its preferred form, structuralmodifications may be made without departing from the scope of the sameas defined in the appended claims.

I claim as my invention:

1. In a device for producing oscillograms, the combination with alight-prom receptacle, of means for supporting a sensitized member andfor rotating the member at a substantially constant speed, and means forequally exposing all parts of the sensitized member.

2. In a device for producing polar oscillograms, the combination with alight-proof receptacle, or" means for rotating a sensitized film at apredetermined speed, and means for exposing substantially all portionsof the said film for equal lengths of time.

3. In a device for producing polar oscillograms, the combination with alight-proof receptacle, of means for rotating a sensitized film at apredetermined speed, means for attaching the said device operatively toan oscillograph, and means for equally exposing various portions of thesaid film.

4:. A device for producing polar oscillopredetermined constant speed.

grams comprising a light-proof receptacle having a slit therein, meansfor rotating a sensitized film contained the "cm at a predeterminedspeed and a shutter having a triangular shaped slit therein that (reopenates with the slit in the receptacle to expose each point of thesensitized film for an equal length 0i time.

5. A device for producing polar oscillograms comprising a light-proofreceptacle having a slit therein, means for rotating a sensitized filmcontained therein, a shutter having a trangular shaped slit thereinfiorcooperating with the slit to expose each point of a sensitized film anequal lengthot time and means for operating the said shutter. I

6. In a device for producing polar oscillograms, the combination with alight-proof receptacle having a slit therein, of a shutter having atriangular shaped slit therein for equally exposing each point of asensitized film, means for operating the said shutter, and a motor forrotating and supporting the film.

7. A device for producing circular oscillograms comprising a light-proofreceptacle having a rectangular shaped slit therein, a shutter having atriangular shaped slit therein to cooperate with the rectangular shapedslit for exposing all parts of a sensitized film equal lengths of time,and means for rotating the sensitized film at asubstantially constantspeed. 7 a v 8. A device for producing oscillograms comprising means forrotating a sensitized circular member at a predetermined constant speedand means for equally exposing each portion of the said member.

9. A camera comprising a light-proof receptacle having a rectangularshaped slit therein, a shutter having a triangular shaped slit thatcooperates with the rectangular shaped slit to equally expose all partsofa sensitized film in the light-proof receptacle and means for rotatingsaid film at a sub stantially constant speed.

10. A camera comprising a circular lightproof receptacle having arectangular slit extending along one of its radii, a shutter having aslit therein for cooperating with the slit in the light-proof receptaclefor equally exposing all parts of sensitized film contained in thelight-proof receptacle and a motor for rotating the said film at a 11. Acamera comprising a circular lightproot receptacle havi a rectangularslit extending along one of its radii, a shutter having atriangularshaped slit therein for cooperating with the slit in the light-proofreceptacle for equally exposing all parts of asensitized film containedin the light-proof receptacle and a motor for supporting and rotatingthe film.

1 operating with the slit in the cover for 12. A camera comprising acircular base In testimony whereof, I have hereunto having a cavitytherein, a cover for the cavsubscribed my name this 29th day of Dec. 10ity having a slit therein and means for se- 1913. curing the same to thebase, a shutter for 00- LEWIS W. OHUBB.

equally exposing all parts of a sensitized Witnesses: film and means forrotating said film at a O. W. A. OETTING, predetermined speed. B. B.HINES.

(topic: of this patent may be obtained for five cents each, byaddressing the "Commissioner of l'atentl,

' Washington. D. G.

